Casing cutter



Patented July 3, 1923.

PATENT OFFICE.

ARTHUR DIX, 0F TAFT, CALIFORNIA.

' cAsING CUTTER.

Application led July 12, 1921. Serial N50. 484,031.

ing oil wells, being more particularly a de vice for cutting oil' the casing in an oil well.

It sometimes happens that in order to remove a casing from a well it is necessary to cut off such casing andthe principal object of my invention is to produce a casing cutter of the class described rvwhich may be efficiently operated for the desired purpose.

Other objects and advantages will appear hereinafteu from the following specification and drawings. v

Referring to the drawings, which are for illustrative purposes only,

Fig. 1 is a vertical sectional view of a casing cutter embodying a form of my invention, the cutter beingI shown within the casing and the parts being in the position assumed just prior to the cutting operation.

Fig. 2 is a cross sectional plan view on line 2 2, Fig. 1. f

Fig. 3 is a cross sectionalplan view on line 3 3, Fig. 1. v

Fig. 4 is a cross sectional plan viewpon line 4 4, Fig. 1. f

Fig. 5 is a cross sectional plan view on line 5 5, Fig. 1.

Fig. 6 is an inverted sectional plan view on line 6 6, Fig. 1.

Fig. 7 is an enlarged vertical sectional view of the upper end of the casing cutter.

Fig. 8 is a sectional view on lirne- 8 8, 7, such view being on a smaller scale,

an Y.

Fig. 9 is a sectional plan view ofl one of the latch bars shown in Fig. 7 together with a dog operated thereby, j

11 designates a casing of a well vwhich casing is to be cut by the casing cutter.

12 designates a drill cable to which is secured a pull rod 13 by means of a coupling indicated in dotted lines at 14. The pull rod slidably extends through the upper end of the cutter which upper end may be designated a casing gripping device or trlp spear 15, such trip spear having a. stuiing box 16 at the upper end thereof by means vof which-dirt and otherforeign matter are prevented from passing downwardly into the tool around the pull -rod 13. The upper end of the trip spear terminates in a circular flange 18, the spear under such flan e being circular in cross section and havlng tapered walls or faces 19 which receive slips 20, such slips having a series of teeth 21 on their outer face arranged to engage t e inside of the casing for the purpose hereinafter described.

The inside faces of the slips are also provided with teeth 23 which are arranged to be engaged by upper dogs 24 yieldingly held in such engagement by means of coiled springs 25, each dog 24 is provided with a beveled face 26 arranged at one side thereof, such 'beveled face being arranged to be engaged by wedges 27 formed on the sides of latch bars 28, such latch bars extending upwardly through a recess 29 formed in the trip spear 15, the slips-20 having slots 30 so as to provide clearance for the latch bars. The upper ends of the latch bars slidably extend through the flange 18 and upwardly therefrom a short distance as shown in Fig. 7 of the drawings. A

31 designates a ring which engages under the lower end of the slips 20, such ring being yieldingly held in such engagement by means of a coiled spring 32, the lower end of which rests upon and engages a circular liange 37 formed on the trip spear, adjacent er near the lower end of the same. The ring 31 is held against the spring 32 by means of lower dogs 34 which engage the upper face of the ring, such dogs being' arranged to beengaged by wedges 35 on the latch bars 28, as vhereinafter described. The lower end of the trip threaded upper end of a barrel or pipe section? 36, such pipe section being of slightly smaller diameter than the inner diameter of the casing. The upper end of the barrel is provided with a plurality of inwardly extending ribs 40, which ribs are engaged by a sliding block 41 slotted to receive such ribs, the barrel being stationary during the operation of the cutter, the sliding block I spear ,15 is exteriorly threaded to recelve the 41 may move vertically but is prevented .from rotating in thebarrel'. The pull rod 13 at this point is provided with outwardly extending ribs 42 which engage in slots 43 in the sliding block, such construction and engagement of the block with ,the rod 13 and barrel 40 permitting a vertical sliding movement of the pull rod but preventing rotative movement of the pull rod.

is a spirally threaded shaft which is secured in any well..known manner to the pull rod 13 so that the pull rod and such v shaft are in fact in rigid relation with ref spect to each other. The threaded shaft 45 engages an interiorly threaded rotary pipe 46 by means of which the vertical reciprocal movement of the pull rod is converted into a rotary movement of the rotary pipe 46. The lower end of the rotary pipe 46 is interiorly threaded to receive the threaded upper end 47 of a sleeve 48. The rotary pipe 46, the sleeve 48 and associated parts are permitted to freely rotate in the barrel 36 but are prevented from vertical longitudinal movement therein by a split bronze bearing 49 secured to the barrel 36 by means of set screws 50, thelsleeve 48 above such bearing being provided with an outwardly extending circular flange 51 which engages between the lower end of the pipe 46 and the upper face of the bearing 49, the lower face of the bearing 49 engaging the upper face of a smaller circular flange 52 formed on the sleeve 48. The lower end of the sleeve 48 is provided with an enlarged rounded head 55, the upper face 56 of which eX- tends outwardly under a circular knife block or holder 57, such knife block 57 having formed on its under face a series of radially disposed ratchet teeth 58 arranged to be engaged by dogs 59 mounted in ways 60 formed 1n the head 55. The dogs 59are yieldingl held in engagement with the ratchet teet 58 by means of coiled sprin 61 held behind the dogs by means of threa ed plugs 62. The head 55 is also provided with a stutling box 65 for preventing an entry of dirtto the interior of the cutter, the interior of the cutter being l preferably filled with oil, such stufiing box also prevents the loss of such oil.

The knife block 57 in the form shown is provided with radially disposed slots 67 in each of which is arranged a knife blade 68, each knife blade being elastically held in retracted position by means of a flat spring 69, the inner endof each blade engages a wedge formed on. a feed block 7l, the upper end of such feedblock being threaded into the pipe section or barrel 36, The lower end of the pipe section or barrel 36 is stripped of its threads and forms a bearmg for the upper end of the knife block 57, such construction being for the purpose of permitting the knife block 57 to rotate freely on the lower end of the pipe section or barrel 36. rlhe inner ends of the knife blades 68 each engage a wedge, as heretofore referred to, such wedges being'formed on flat faces 74 on the feed block, such flat'faces being engaged by corresponding faces on the inside of the rlhe cutter is operated in4 the followingY The pull rod 13 having been secured to the cable 12, heretofore referred to, the cutter Ais let down into the well to the point where it is desired to cut the casing. Now, by givin the cable an upward pull, the slips 20 wi l engage the inner face of the casing and be held in such engagement by means of dogs 24 engagin the teeth on the inner face of the slips. Tis engagement of the slips with the casing prevents turning of certain parts of the cutter during 'the cutting operation, that is, the pipe section or barrel 36 being secured to the lower end of the casing spear, as heretofore described, is stationary and is prevented from moving up and down due to the engagement of the slips with the casing.

Now, by operating the cable up and down, by attaching the same to the walking beam of the drilling mechanism and preferably by letting enough slack in the cable to permit l the Walking beam to work and no more, the up and down movement imparted to the pull rod 13 by the cable is converted into a rota movement through the medium of a sha 45, which, in turn, rotates the sleeve 48.

The connection between the head 55 on the sleeve 48 and the knife block 57 being of the character of a ratchet and pawl, it is understood that the movement of the sleeve 48 in one direction is transmitted to the knife block 57 and through the engagement of the knife block withthe feed block 71, such movement is transmitted to the feed block.

Thev feed block being threaded into the lower end`of the stationary barrel 36, is caused by such movement' to move upwardly in the knife block 57 and such upward movement, due to the engagement of the wedges 70 with the knives, brings the knives into engagement; with the casing and the cuttin operation is carried on until the lower end of the feed block has moved above and out of engagement with the knives, `such action taking place when the kniveshave expanded a sufficient distance to entirely cut through the casing. When the feed block moves above the knives, the springs 68 retract the knives 69 into a position inside the ,outert circumference of the knife block 57.

The cutting operation having been inished, it isunderstood that the cutter is removed from the well by permitting some -slack in the cable thereby permitting the thereby freeing the slips. The latch bars, during their downward movement, just described, also operate the dogs 34 to release the ring 31 which is forced upwardly against the lower ends of the slips 20 thereby forclngthe slips out of engagement with the casing and freeing the tool so that the tool may be withdrawn from the casing.

I claim as my invention:

1. A casing cutter comprising a trip spear; a pull rod slidably extending through said spear; a plurality of slips mounted on said spear; teeth formed on the outer face of said slips arranged to engage the inner face of the casing; teeth on the inner face of each slip; upper dogs mounted in said spear arranged to engage the teeth on the inside of said slips; means for elastically holding such dogs in engagement with the teeth; a ring on said spear engaging the under face of said slips; a coiled spring under said ring arranged to elastically hold said ring in engagement with said slips; a plurality of lower dogs in said spear engaging the upper face of said ring; means for elastlcally holding said lower dogs in engagement with said ring; a plurality of latch bars slidably mounted in said spear; means yon each latch bar for simultaneously .detracting'its associated upper and lower dogs; means on said pull rod for operating said latch bars; a plurality of cutting blades and means operated by said pull rod for operating said blades. l

2. A casing cutter comprising a trip spear; a pull rod slidably extending through said spear; a plurality of slips mounted on v said spear; teeth formed on the outer face of are brought into cutting action on said cassaid slips arranged to engage the inner face of the casing; teethon the inner face of each slip; upper dogs mounted in said spear ar' ranged to engage the teeth on the inside of said slips; means for elastically holding such dogs in engagement with the teeth; a

plurality -of latch bars in said spear; means on each latch bar for simultaneously moving said dogs out of engagement with the teeth on /the slips; means on said pull rod for operating said latch bars; a plurality of cutting blades and means operated by said pull rod for operating said blades.

3. A casing cutter comprisin caslng gripping means; a ullv rod sli ably. extending through sai gripping means; rotatably reciprocating means operated by said pull rod; a knife holder; aplura1ity of knives mounted in said knife holder; means associated with said rotatably reciproeating means for rotating said knife holder in one direction; means operated by said reciprocating means whereby said knives ing and means for yieldingly holding' said knives in retratedposition.

4. A casing cutter comprising casing said V ing through said gripping means; a rotas tably reciprocating sleeve on said pull rod operated thereby; a knife holder; means operated by said sleeve for rotatin said knife holder in one direction; a plurallty of knife blades in said knife holder; spr-ings engaging each blade for yieldingly holding said blades in inoperative position; and a feed block operated by said knife holder arranged to engage the inner ends of said blades and move the blades into cutting position; said feed block being arranged to pass out of engagement withtsaid blades upon completion of the cutting operation thereby permitting retraction of the blades by said springs.

6. A casing cutter comprising casing gripping means; a pull rod slidably extending through said gripping means; a rotatably reciprocating sleeve on said pull rod operated thereb 'a knife holder; means opf.

erated by said s eeve for rotating said knife holder in one direction; a plurality of knife blades in said knife holder; a feed block, wedges on said feed block engaging said blades; means for operating said feed block by said knife holder to move said blades into engagement with said casing and con-. tinuing such movement of the feed block above said knife holder to release said 'blades; means for retracting said knives;

and means for releasingL said gripping means.

7. A casing cutter comprising casing gripping means; a pull rod slidably extending through said gripping means; a stationary barrel secured to said gripping means; a rotary pipe in said stationary barrel; means operated by said pull rod for rotating said pipe; a sleeve secured to said pipe; aknife block; a series of knife blades in said knife block; means operated in said sleeve for rotating said knife block in one direction; a feed block operated by said knife block to move said knife blades into o p erative position; means for retracting said bliades on completion of said cutting operation; and means for'releasing said gripping means.

8. A casing cutter comprising 'casing gripping means; a stationary barrel secured to said gripping means; a pull rod slidably means on said barrel for preventing rotative movement of said pull rod; a threaded shaft fixed to said pull rod; an interiorly threaded rotary pipe engaging said threaded shaft whereby reciprocating vertical movementof the pull rod causes said pipe to rotate; a sleeve Vsecured to Said rotary pipe; means on said barrel for preventing vertical movement of said sleeve; a plurality of cutting blades; means operated by said sleeve for moving -said blades into cutting position; and means for' detracting said gripping means from the casing.

9. ln a device of the character described, the combination of: aspear; a plurality of slips on said spear; teeth formed onv the outer faces of said slips for engaging the inner face of the casing; teeth formed on the inner faoes'of said slips; pawls held by `said spear adapted to engage said inner teeth; resilient means normally holding said i slips in retracted position, said resilient means being compressiblev so as to permit 'engagement of said slips With said casing,

by a jerk upon ysaid spear; bars having means formedthereupon for removing said pawls from engagement with said inner teeth when it is desired to release said slips from said casing; and means for actuatingy said bars to release said pawls.

In testimony whereof, I have hereunto set' 

